A boy aged 14 was hit in the face outside numbers 23-25 Pembroke Road, Larkfield, shortly before 9.30pm last night.
He suffered a cut and required one stitch.
Detectives are also probing an attack at Pladda Fields near to Pladda Avenue in the Port where a 16-year-old boy was also hit in the face with a bottle and punched.
It happened sometime between 6 and 9pm last night and left the victim with a two centimetre cut to his lip, chin and a laceration to his jaw.
Both are being treated as serious assaults and police are appealing for any witnesses to come forward.
Anyone with information relating to either of the attacks is urged to contact Greenock CID on 101 or Crimestoppers anonymously on 0800 555 111.